When you want to Pump Up the Volume, CD City is home to the largest collection of bargain-priced CDs anywhere. The store has aisles and aisles of neatly arranged pop, hip-hop, jazz, world and country. They shine, however, as music salvagers, literally buying truckloads of music, much of which ends up in their amazing two-for-$5 bins. Like Christian Slater's Hard Harry DJ character, stuck in the hinterlands of Arizona, you'll find obscure gems aplenty to amaze and delight you and your friends (and your neighbors, if you play it loud enough). Be forewarned: Knowledgeable shoppers have the edge when rooting through the thousands of unsorted CDs. It's not uncommon for aficionados to carry handbaskets with 20 or 30 albums to the checkout after a foray. It's not quite free music, but it is a major blow for freedom from high corporate prices.